2014-01-23 18:47:39

by Zoltan Kiss

[permalink] [raw]
Subject: [PATCH net-next] bonding: Use do_div to divide 64 bit numbers

Nikolay Aleksandrov's recent bonding option API changes (25a9b54a and e4994612)
introduced u64 as the type of downdelay and updelay. On 32 bit the division and
modulo operations cause compile errors:

ERROR: "__udivdi3" [drivers/net/bonding/bonding.ko] undefined!
ERROR: "__umoddi3" [drivers/net/bonding/bonding.ko] undefined!

This patch use the do_div macro, which guaranteed to do the right thing.

Signed-off-by: Zoltan Kiss <[email protected]>
---
drivers/net/bonding/bond_options.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 4cee04a..4f94907 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -18,6 +18,7 @@
#include <linux/rcupdate.h>
#include <linux/ctype.h>
#include <linux/inet.h>
+#include <asm/div64.h>
#include "bonding.h"

static struct bond_opt_value bond_mode_tbl[] = {
@@ -727,19 +728,20 @@ int bond_option_miimon_set(struct bonding *bond, struct bond_opt_value *newval)

int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
{
+ u64 quotient = newval->value;
+ u64 remainder = do_div(quotient, bond->params.miimon);
if (!bond->params.miimon) {
pr_err("%s: Unable to set up delay as MII monitoring is disabled\n",
bond->dev->name);
return -EPERM;
}
- if ((newval->value % bond->params.miimon) != 0) {
+ if (remainder != 0) {
pr_warn("%s: Warning: up delay (%llu) is not a multiple of miimon (%d), updelay rounded to %llu ms\n",
bond->dev->name, newval->value,
bond->params.miimon,
- (newval->value / bond->params.miimon) *
- bond->params.miimon);
+ quotient * bond->params.miimon);
}
- bond->params.updelay = newval->value / bond->params.miimon;
+ bond->params.updelay = quotient;
pr_info("%s: Setting up delay to %d.\n",
bond->dev->name,
bond->params.updelay * bond->params.miimon);
@@ -750,19 +752,20 @@ int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
int bond_option_downdelay_set(struct bonding *bond,
struct bond_opt_value *newval)
{
+ u64 quotient = newval->value;
+ u64 remainder = do_div(quotient, bond->params.miimon);
if (!bond->params.miimon) {
pr_err("%s: Unable to set down delay as MII monitoring is disabled\n",
bond->dev->name);
return -EPERM;
}
- if ((newval->value % bond->params.miimon) != 0) {
+ if (remainder != 0) {
pr_warn("%s: Warning: down delay (%llu) is not a multiple of miimon (%d), delay rounded to %llu ms\n",
bond->dev->name, newval->value,
bond->params.miimon,
- (newval->value / bond->params.miimon) *
- bond->params.miimon);
+ quotient * bond->params.miimon);
}
- bond->params.downdelay = newval->value / bond->params.miimon;
+ bond->params.downdelay = quotient;
pr_info("%s: Setting down delay to %d.\n",
bond->dev->name,
bond->params.downdelay * bond->params.miimon);


2014-01-23 20:44:56

by Nikolay Aleksandrov

[permalink] [raw]
Subject: Re: [PATCH net-next] bonding: Use do_div to divide 64 bit numbers

On 01/23/2014 07:47 PM, Zoltan Kiss wrote:
> Nikolay Aleksandrov's recent bonding option API changes (25a9b54a and e4994612)
> introduced u64 as the type of downdelay and updelay. On 32 bit the division and
> modulo operations cause compile errors:
>
> ERROR: "__udivdi3" [drivers/net/bonding/bonding.ko] undefined!
> ERROR: "__umoddi3" [drivers/net/bonding/bonding.ko] undefined!
>
> This patch use the do_div macro, which guaranteed to do the right thing.
>
> Signed-off-by: Zoltan Kiss <[email protected]>
> ---
> drivers/net/bonding/bond_options.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index 4cee04a..4f94907 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
> @@ -18,6 +18,7 @@
> #include <linux/rcupdate.h>
> #include <linux/ctype.h>
> #include <linux/inet.h>
> +#include <asm/div64.h>
> #include "bonding.h"
>
> static struct bond_opt_value bond_mode_tbl[] = {
> @@ -727,19 +728,20 @@ int bond_option_miimon_set(struct bonding *bond, struct bond_opt_value *newval)
>
> int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
> {
> + u64 quotient = newval->value;
> + u64 remainder = do_div(quotient, bond->params.miimon);
Hi Zoltan,
Thanks for fixing this, a few comments though:
bond->params.miimon can be 0 here that's why there's a check afterwards,
also please separate the local variable definitions from the body with a
new line.
The same applies for downdelay.

Nik
> if (!bond->params.miimon) {
> pr_err("%s: Unable to set up delay as MII monitoring is disabled\n",
> bond->dev->name);
> return -EPERM;
> }
> - if ((newval->value % bond->params.miimon) != 0) {
> + if (remainder != 0) {
> pr_warn("%s: Warning: up delay (%llu) is not a multiple of miimon (%d), updelay rounded to %llu ms\n",
> bond->dev->name, newval->value,
> bond->params.miimon,
> - (newval->value / bond->params.miimon) *
> - bond->params.miimon);
> + quotient * bond->params.miimon);
> }
> - bond->params.updelay = newval->value / bond->params.miimon;
> + bond->params.updelay = quotient;
> pr_info("%s: Setting up delay to %d.\n",
> bond->dev->name,
> bond->params.updelay * bond->params.miimon);
> @@ -750,19 +752,20 @@ int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
> int bond_option_downdelay_set(struct bonding *bond,
> struct bond_opt_value *newval)
> {
> + u64 quotient = newval->value;
> + u64 remainder = do_div(quotient, bond->params.miimon);
> if (!bond->params.miimon) {
> pr_err("%s: Unable to set down delay as MII monitoring is disabled\n",
> bond->dev->name);
> return -EPERM;
> }
> - if ((newval->value % bond->params.miimon) != 0) {
> + if (remainder != 0) {
> pr_warn("%s: Warning: down delay (%llu) is not a multiple of miimon (%d), delay rounded to %llu ms\n",
> bond->dev->name, newval->value,
> bond->params.miimon,
> - (newval->value / bond->params.miimon) *
> - bond->params.miimon);
> + quotient * bond->params.miimon);
> }
> - bond->params.downdelay = newval->value / bond->params.miimon;
> + bond->params.downdelay = quotient;
> pr_info("%s: Setting down delay to %d.\n",
> bond->dev->name,
> bond->params.downdelay * bond->params.miimon);
>

2014-01-23 21:18:34

by Nikolay Aleksandrov

[permalink] [raw]
Subject: Re: [PATCH net-next] bonding: Use do_div to divide 64 bit numbers

On 01/23/2014 09:44 PM, Nikolay Aleksandrov wrote:
> On 01/23/2014 07:47 PM, Zoltan Kiss wrote:
>> Nikolay Aleksandrov's recent bonding option API changes (25a9b54a and e4994612)
>> introduced u64 as the type of downdelay and updelay. On 32 bit the division and
>> modulo operations cause compile errors:
>>
>> ERROR: "__udivdi3" [drivers/net/bonding/bonding.ko] undefined!
>> ERROR: "__umoddi3" [drivers/net/bonding/bonding.ko] undefined!
>>
>> This patch use the do_div macro, which guaranteed to do the right thing.
>>
>> Signed-off-by: Zoltan Kiss <[email protected]>
>> ---
>> drivers/net/bonding/bond_options.c | 19 +++++++++++--------
>> 1 file changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
>> index 4cee04a..4f94907 100644
>> --- a/drivers/net/bonding/bond_options.c
>> +++ b/drivers/net/bonding/bond_options.c
>> @@ -18,6 +18,7 @@
>> #include <linux/rcupdate.h>
>> #include <linux/ctype.h>
>> #include <linux/inet.h>
>> +#include <asm/div64.h>
>> #include "bonding.h"
>>
>> static struct bond_opt_value bond_mode_tbl[] = {
>> @@ -727,19 +728,20 @@ int bond_option_miimon_set(struct bonding *bond, struct bond_opt_value *newval)
>>
>> int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
>> {
>> + u64 quotient = newval->value;
>> + u64 remainder = do_div(quotient, bond->params.miimon);
> Hi Zoltan,
> Thanks for fixing this, a few comments though:
> bond->params.miimon can be 0 here that's why there's a check afterwards,
> also please separate the local variable definitions from the body with a
> new line.
> The same applies for downdelay.
>
> Nik
In fact since we don't need the u64 and newval->value is limited to
INT_MAX, can't we simply cast it to (int) and avoid the do_div entirely ?

>> if (!bond->params.miimon) {
>> pr_err("%s: Unable to set up delay as MII monitoring is disabled\n",
>> bond->dev->name);
>> return -EPERM;
>> }
>> - if ((newval->value % bond->params.miimon) != 0) {
>> + if (remainder != 0) {
>> pr_warn("%s: Warning: up delay (%llu) is not a multiple of miimon (%d), updelay rounded to %llu ms\n",
>> bond->dev->name, newval->value,
>> bond->params.miimon,
>> - (newval->value / bond->params.miimon) *
>> - bond->params.miimon);
>> + quotient * bond->params.miimon);
>> }
>> - bond->params.updelay = newval->value / bond->params.miimon;
>> + bond->params.updelay = quotient;
>> pr_info("%s: Setting up delay to %d.\n",
>> bond->dev->name,
>> bond->params.updelay * bond->params.miimon);
>> @@ -750,19 +752,20 @@ int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
>> int bond_option_downdelay_set(struct bonding *bond,
>> struct bond_opt_value *newval)
>> {
>> + u64 quotient = newval->value;
>> + u64 remainder = do_div(quotient, bond->params.miimon);
>> if (!bond->params.miimon) {
>> pr_err("%s: Unable to set down delay as MII monitoring is disabled\n",
>> bond->dev->name);
>> return -EPERM;
>> }
>> - if ((newval->value % bond->params.miimon) != 0) {
>> + if (remainder != 0) {
>> pr_warn("%s: Warning: down delay (%llu) is not a multiple of miimon (%d), delay rounded to %llu ms\n",
>> bond->dev->name, newval->value,
>> bond->params.miimon,
>> - (newval->value / bond->params.miimon) *
>> - bond->params.miimon);
>> + quotient * bond->params.miimon);
>> }
>> - bond->params.downdelay = newval->value / bond->params.miimon;
>> + bond->params.downdelay = quotient;
>> pr_info("%s: Setting down delay to %d.\n",
>> bond->dev->name,
>> bond->params.downdelay * bond->params.miimon);
>>
>
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>

2014-01-23 22:25:28

by Sergei Shtylyov

[permalink] [raw]
Subject: Re: [PATCH net-next] bonding: Use do_div to divide 64 bit numbers

Hello.

On 23-01-2014 22:47, Zoltan Kiss wrote:

> Nikolay Aleksandrov's recent bonding option API changes (25a9b54a and e4994612)

You should also specify those commits' summary lines.

> introduced u64 as the type of downdelay and updelay. On 32 bit the division and
> modulo operations cause compile errors:

> ERROR: "__udivdi3" [drivers/net/bonding/bonding.ko] undefined!
> ERROR: "__umoddi3" [drivers/net/bonding/bonding.ko] undefined!

> This patch use the do_div macro, which guaranteed to do the right thing.

> Signed-off-by: Zoltan Kiss <[email protected]>
> ---
> drivers/net/bonding/bond_options.c | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)

> diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
> index 4cee04a..4f94907 100644
> --- a/drivers/net/bonding/bond_options.c
> +++ b/drivers/net/bonding/bond_options.c
[...]
> @@ -727,19 +728,20 @@ int bond_option_miimon_set(struct bonding *bond, struct bond_opt_value *newval)
>
> int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
> {
> + u64 quotient = newval->value;
> + u64 remainder = do_div(quotient, bond->params.miimon);

Empty line after declarations wouldn't hurt here.

> @@ -750,19 +752,20 @@ int bond_option_updelay_set(struct bonding *bond, struct bond_opt_value *newval)
> int bond_option_downdelay_set(struct bonding *bond,
> struct bond_opt_value *newval)
> {
> + u64 quotient = newval->value;
> + u64 remainder = do_div(quotient, bond->params.miimon);

And here.

WBR, Sergei

2014-01-24 18:27:41

by Zoltan Kiss

[permalink] [raw]
Subject: Re: [PATCH net-next] bonding: Use do_div to divide 64 bit numbers

On 23/01/14 21:18, Nikolay Aleksandrov wrote:
>> Hi Zoltan,
>> Thanks for fixing this, a few comments though:
>> bond->params.miimon can be 0 here that's why there's a check afterwards,
>> also please separate the local variable definitions from the body with a
>> new line.
>> The same applies for downdelay.
>>
>> Nik
> In fact since we don't need the u64 and newval->value is limited to
> INT_MAX, can't we simply cast it to (int) and avoid the do_div entirely ?
Yep, that's even better, thanks for fixing it!

Zoli